ACTION OF DIETHYLSTILBESTROL IN THE CHICK1

Abstract

The adm. of stilbestrol and estrogen to normal-diet chicks inhibited body growth slightly, and stilbestrol had a very marked inhibitory action on the development of combs and gonads. The adrenal glands were hypertrophied in the stilbestrol series, but the wts. of liver, pancreas, and intestine and the intestine length were not significantly greater than the control. In this respect, the action of the stilbestrol is different from estrogen. Injection of stilbestrol into capons, alone and in combination with testosterone-prbpionate, showed that the effect on the comb was a result of suppressing secretion of endogenous androgen. However, the adm. of 0.200 mg. daily produced combs in normal chicks which were only \ the size of the capon combs. The possibility of the presence of extra-gonadal comb-growth-promoting substance in the chick is considered. Treatment of pullets and limited-diet chicks further support the hypothesis that the action of stilbestrol on the comb is indirect. Pullets given dosages of stilbestrol ranging from 0.0005 mg. to 0.010 in combination with androgen have combs which do not differ significantly. Pullets on extremely limited-diet show that stilbestrol will actually stimulate some comb-growth when administered directly into the comb. When stilbestrol and testosterone-propionate were given at the same time in these chicks, the comb response was almost exactly the same as the summation of the effects of these 2 preps. when given separately.